2012 Honda Accord Automatic.
100,000 Miles

So I first noticed a problem with a slight hesitation in acceleration with this car about a month ago. From a stop when you’d hit the gas pedal it would sort of crawl for a couple seconds, then bam, start going like normal. The “emissions control” light also had just come on.

Took it in to a AAA repair shop. They said the light was just indicating a sensor detected it running rich, but that it wasn’t showing that now. They did check the transmission fluid too and said that was in an acceptable range. They also claimed to not experience the same acceleration issue while drovong it. They said it was fine and bring it back if it keeps happening. Emissions light remained off on the drive home and for the few weeks it was driven after that. The acceleration issue seemed to go away too.

Go on a couple weeks vacation and got home last night, and planed to drive it this evening.

Well first when I tried to start the car the battery is dead. Dead dead. No lights, can’t shift into neutral. That I assume was from it sitting for a couple weeks without being started. No big deal I have another car to jump it but I have to get it out of the driveway to jump it. So I pop the tab next to the shifter and put it in neutral that way. Jump the car. All seems fine.

Start driving down the road and notice the emissions light is on again and it is crawling. Once I get it up to about 20mph it “bumps” like it can’t or is having trouble shifting. After I hit 20mph it seems to accelerate better, more naturally, but the rpms are sitting at around 2.5-3k. Never took it out of the neighborhood. Never went faster than 25-30 mph.

I did try using the manual shift starting at D1, which accelerated fine, then up to D2, and D3 and those all seem to be fine. But when it is set to regular automatic drive it still seems stuck and doesn’t reaccelerate normally from a stop.

Is my transmission shot? Maybe something simpler (hopefully)?

 

Typically if there is a fault with any of the transmission control components you'd get a flashing "D4" light on the dash but not always. It's important to determine if the problem is engine related or transmission related. The emissions control light makes me think its more of an engine problem but what your describing does sound like a transmission problem. You could have a failure of a transmission related sensor or solenoid or a internal hydraulic failure. A Honda dealer could connect their factory scan tool and scan the transmission control computer for codes, activate the different solenoids and also monitor the readings of the sensors. My guess is a transmission solenoid or a torque converter problem.

 

Thanks for the reply. So after doing some other research it seems what happened was it kicked into limp home mode for some reason.

Emissions light is back off now and driving fine again. No hitch in the giddy up at all. Gonna get it back in soon to make sure but after pulling codes looks like it is still an intermittently malfunctioning o2 sensor causing the emissions light. Not sure if it needing a jump (and me being somewhat impatient and trying to start it twice without letting it charge enough) could have had something to do with why it went into limp mode. Thankfully doesn’t seem to be the transmission.

 

Yeah a faulty 02 sensor, especially if upstream, can wreck havoc when it comes to check engine lights, limp mode & faulty air/fuel ratio readings (which cause the ecu to run the car excessively rich or lean).
Excessively rich or lean running conditions can cause problems but going into limp mode is gonna be cause for a major drop in performance and things like poor throttle response and hesitation.
Sounds like you found the problem!

What region is your car from? I've never heard of a "Emissions Light"